Tesco Replaces CEO as Trading Weakens

Dave Lewis to Replace Philip Clarke as Chief Executive

LONDON—Tesco PLC said Chief Executive Philip Clarke would step down in October to be replaced by Unilever PLC executive Dave Lewis, as the U.K.'s largest retailer issued a new profit warning.

Tesco said on Monday that trading in recent weeks had been more challenging than anticipated and profit in the first half of its financial year would be below expectations. It is Tesco's second profit warning in Mr. Clarke's three year tenure,...